I didn't know about SX and minis...are you really really sure about that? Not that I don't trust you, but this really surprises me!
Anyway I have an SX and I use standard size dvds...I burned the first at 1x and it didn't work, I'm burning everything at 4x and they work like a charm, no DRE, no freezes, no glithces etc. So maybe is your GC laser or your burner? Really, 4x burning for me works. Slower speeds give me problems. And they confirmed me this thing of the 4x speed on maxconsole boards too=)
Anyway to all of you interested in the qoob, I suggest to buy it, is really a great thing and works fine with me, even with multigame discs (2 or+games on a single disc...nice!). For those who don't need the extra features (like me) but only backup playing go for the sx.